Modern ABS systems are significantly better at handling these situations, but are still subject to drastically increased stopping distances. The ... ]]> I often read on forums somebody saying “Well, I don’t need snow tires because I have ABS.” Or worse, “I don’t need snow tires because I have AWD.” The problem with the latter statement is obvious (AWD does not help you stop or turn) but the problem with the former is less obvious. ABS actually increases the need for good rubber between the car and the road.

Having good tires is the single biggest factor in winter driving. This doesn’t just mean having snow tires. Having bald or worn tires is worse than having all seasons. Even if you do not live in an area where it snows enough to consider purchasing snow tires, it is very important to check your tire tread depth using the penny test. If you have insufficient treadlife remaining, replace your tires before it starts snowing.

But why does ABS increase the need for good tires? ABS works using a technique called “cadence braking” to prevent the wheels from skidding during braking. When the ABS controller detects a wheel has stopped spinning (locked) it releases the brake pressure on that wheel until it spins again. It then increases the pressure until it stops, and so on. More sophisticated ABS systems can do this quite fast, and can usually shorten braking distance on dry pavement compared to a human executing the cadence braking maneuver, and somtimes even a skilled driver executing a threshold braking maneuver. In any case, the tire’s grip still matters because a stickier tire will grip longer before the wheel locks requiring less ABS action.

But we aren’t talking about dry pavement, we’re talking about winter driving on snow and ice. On snow and ice ABS drastically increases stopping distances. In snow, when the wheels lock a wedge of snow builds up in front of the tire causing a significant retarding effect. But ABS destroys this effect in its attempt to keep the wheels rolling. As a result, the ABS controller spends much of the time with the brakes released and it takes longer to stop. On ice, the wheels lock up so readily that the ABS hardly applies the brakes at all and stopping distances are nearly doubled compared to a locked wheels slide. The issues seen with snow are also seen in loose gravel and sand.

Modern ABS systems are significantly better at handling these situations, but are still subject to drastically increased stopping distances. The solution to this is twofold. The first factor is to make sure you are using good tires. As stated above, good tires mean there will be more braking ability before the wheels lock and the ABS system intervenes. The second factor is to be aware that the purpose of ABS is to allow the drive to retain some steering ability during braking and not to improve stopping distances.

There is a sophisticated solution to the problem of having to make an emergency stop where the ABS effect is detrimental. You can deliberately skid the car 90 degrees perpendicular to the original direction of motion. The car will continue to skid forward in the same direction, but all four wheels will be sliding accumulating the “wedge” and will enable a quicker stop. However, this is a difficult maneuver to get right and requires enough parking lot practice to make it automatic before using it in an emergency. In the meantime, just get some good tires and remember that ABS doesn’t help you stop.

Periodic maintenance of the ABS system is required and should be done either at the dealership or by a suitably qualified service depot. Brake fluid breaks down ... ]]> In simple terms, the ABS or Anti-lock Braking System is a safety feature that comes with most vehicles in North America these days. ABS was first developed for aircraft as a tool for aiding the pilot to stop the aircraft in adverse conditions. The technology has now found its way into the motor vehicle industry and it is, in most cases a standard feature with new vehicles. It becomes a bit confusing for a driver who drives a vehicle equipped with ABS when he or she does not understand a few simple things about the feature. To assume that the ABS takes full control of the vehicle when in tricky driving conditions is a misconception. Driving skills still takes precedence in the actual manoeuvring of the vehicle.

A few basic tips should be able to help the average driver in understanding what to do and how to do it when certain conditions exist. Do not pump the brake pedal instead; apply enough force on the pedal to stop the vehicle quickly. Always allow enough distance and double the distance behind vehicles when driving on wet roads and use better discretion on snowy and icy roads. If you drive one of these four wheel drives, bear in mind that pumping the brakes turns the ABS on and off which results in compromising your braking efficiency. The system was designed to pump the brake for you automatically and faster than you can do it yourself. Concentrate on steering the vehicle. This simple error is what causes a lot of SUV’s to end up in the ditch during wet or wintery weather conditions.

Periodic maintenance of the ABS system is required and should be done either at the dealership or by a suitably qualified service depot. Brake fluid breaks down and loses its chemical properties in vehicles that have ABS so following the manufacturer’s recommendation for service, would save a few dollars over the long term. Unless you are going to repair the ABS system in your vehicle yourself, there is hardly a need to know what the system is comprised of and how it goes about doing its various functions. Usually the layman’s approach is the best way to deal with problems that may pop up.

When you start your vehicle the ABS light in the instrument panel will come on for a few seconds and will then turn off. This is normal and indicates that the ABS is working fine. If the light turns on and stays on then there is a problem. If the normal brakes are still working and it should be, take the car to the dealer for service. If both the ABS and brake lights are on in the instrument panel, it means that you have no brakes. Do not drive this vehicle at all! Have it towed to the dealer for repair as soon as possible.